1. Field of the Invention
The present invention relates to a disk brake for wheels of vehicles and especially for motorcycle wheels, designed to solve some important problems connected with the braking of such vehicles.
It is known that in some vehicles, typically motorcycles, the application of disk brakes has met so far with little success -- in spite of the felt need to replace (especially in a large motorcycles) the drum brakes by more modern and efficient brakes -- due to some problems not easy to solve. In particular, a serious difficulty was represented by the rational placement of the disk, usually arranged to the side of the wheel with the respective calipers, with consequent weight unbalances in the case of motorcycles.
2. Description of the Prior Art
In order to obtain a rational solution of this important problem, it has already been suggested to embody the brake disk in the hub of the vehicle wheel (particularly a motorcycle wheel), attributing to said disk also functions of connection between the actual hub and its flange for attachment of the wheel spokes, and to act on the disk itself with friction pads, carried by brake plates mounted on the wheel axle and discharging their own reactions onto the disk.
This solution, however -- though in theory quite convincing -- has not so far given, for various reasons, any acceptable practical results, so that most motorcycles of all the types being produced at present, continue to adopt the old drum brakes, with all the drawbacks deriving therefrom.
Usually, in carrying out the above solution, the brake plate connecting the hub and the wheel spokes carrying flange, has been placed according to the symmetry plane perpendicular to the axis of the wheel itself. On other occasions, use has been made of two disks, parallel to and equally spaced from said plane. The structures deriving therefrom have been, in most cases, either exceedingly heavy and bulky, as well as expensive, or insufficiently safe, due to their precarious behaviour as to stresses in use; besides, as to the removal of the heat produced by friction, they have not given fully satisfactory results.
Furthermore, in all these brakes of the prior art, the engagement between the friction pads of the brake plates and the brake disk or disks takes place by front contact, as a result of the movement of said plates according to the wheel axis and towards the wheel itself. In these brakes the forces which have to be applied in order to effect the braking, are high in respect of the braking effect obtained, and the cooperation between the friction pads and the disks takes place in a rather abrupt way, resulting in braking which is far less smooth than desirable.